use actix_cors::Cors;
use actix_web::cookie::time::Duration;
use actix_web::middleware::Logger;
use actix_web::{cookie::Key, web, App, HttpResponse, HttpServer};
use clap::Parser;
use db::cache::AppCache;
use db::database::AppDatabase;
use observability::{
    init_tracing_subscriber, install_recorder, prometheus_handler, spawn_http_metrics_poller,
    HttpMetrics, HttpSnapshotGuard, MetricsMiddleware, TracingSpanMiddleware,
};
use sea_orm::ConnectionTrait;
use service::AppService;
use session::config::{PersistentSession, SessionLifecycle, TtlExtensionPolicy};
use session::storage::RedisClusterSessionStore;
use session::SessionMiddleware;

mod args;

use args::ServerArgs;
use config::AppConfig;
use migrate::{Migrator, MigratorTrait};

#[derive(Clone)]
pub struct AppState {
    pub db: AppDatabase,
    pub cache: AppCache,
}

fn build_session_key(cfg: &AppConfig) -> anyhow::Result<Key> {
    if let Some(secret) = cfg.env.get("APP_SESSION_SECRET") {
        let bytes: Vec<u8> = secret.as_bytes().iter().cycle().take(64).copied().collect();
        return Ok(Key::from(&bytes));
    }
    Ok(Key::generate())
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let cfg = AppConfig::load();
    let log_level = cfg.log_level().unwrap_or_else(|_| "info".to_string());
    let otel_enabled = cfg.otel_enabled().unwrap_or(false);
    init_tracing_subscriber(&log_level, otel_enabled);
    tracing::info!(
        app_name = %cfg.app_name().unwrap_or_default(),
        app_version = %cfg.app_version().unwrap_or_default(),
        "Starting application"
    );
    let db = AppDatabase::init(&cfg).await?;
    tracing::info!("Database connected");
    let redis_urls = cfg.redis_urls()?;
    let store: RedisClusterSessionStore = RedisClusterSessionStore::new(redis_urls).await?;
    tracing::info!("Redis connected");
    let cache = AppCache::init(&cfg).await?;
    tracing::info!("Cache initialized");
    run_migrations(&db).await?;
    let session_key = build_session_key(&cfg)?;
    let args = ServerArgs::parse();
    let service = AppService::new(cfg.clone()).await?;
    tracing::info!("AppService initialized");
    let _model_sync_handle = service.clone().start_sync_task();
    let _billing_alert_handle = service.clone().start_billing_alert_task();

    let (shutdown_tx, shutdown_rx) = tokio::sync::broadcast::channel::<()>(1);
    let worker_service = service.clone();
    let worker_handle =
        tokio::spawn(async move { worker_service.start_room_workers(shutdown_rx).await });

    let _otel_guard = if otel_enabled {
        let endpoint = cfg
            .otel_endpoint()
            .unwrap_or_else(|_| "http://localhost:4317".to_string());
        let service_name = cfg
            .otel_service_name()
            .unwrap_or_else(|_| "app".to_string());
        let service_version = cfg
            .otel_service_version()
            .unwrap_or_else(|_| "0.1.0".to_string());
        tracing::info!(endpoint = %endpoint, service = %service_name, "OTLP tracing enabled");
        let guard =
            observability::init_otlp(&endpoint, &service_name, &service_version, &log_level)
                .map_err(|e| anyhow::anyhow!("OTLP init failed: {}", e))?;
        guard
    } else {
        None
    };

    let prometheus_handle = install_recorder();
    let prometheus_handle_arc = std::sync::Arc::new(prometheus_handle);
    let prometheus_handle_data = web::Data::new(prometheus_handle_arc.clone());

    let http_metrics = std::sync::Arc::new(HttpMetrics::new());
    let http_snapshot: HttpSnapshotGuard = std::sync::Arc::new(std::sync::RwLock::new(
        observability::HttpMetricsSnapshot::default(),
    ));
    let http_snapshot_for_poller = http_snapshot.clone();
    spawn_http_metrics_poller(
        http_metrics.clone(),
        http_snapshot_for_poller,
        std::time::Duration::from_secs(15),
    );
    let http_snapshot_data = web::Data::new(http_snapshot);

    let bind_addr = args.bind.unwrap_or_else(|| "127.0.0.1:8080".to_string());
    tracing::info!(bind_addr = %bind_addr, "Listening");
    let http_metrics_server = http_metrics.clone();
    HttpServer::new(move || {
        let cors = Cors::default()
            .allow_any_origin()
            .allow_any_method()
            .allow_any_header()
            .supports_credentials()
            .max_age(3600);

        let session_mw = SessionMiddleware::builder(store.clone(), session_key.clone())
            .cookie_name("id".to_string())
            .cookie_path("/".to_string())
            .cookie_secure(false)
            .cookie_http_only(true)
            .session_lifecycle(SessionLifecycle::PersistentSession(
                PersistentSession::default()
                    .session_ttl(Duration::days(30))
                    .session_ttl_extension_policy(TtlExtensionPolicy::OnEveryRequest),
            ))
            .build();

        let metrics_mw = MetricsMiddleware::new(http_metrics_server.clone());

        App::new()
            .wrap(cors)
            .wrap(session_mw)
            .wrap(Logger::default().exclude("/health"))
            .wrap(metrics_mw)
            .wrap(TracingSpanMiddleware::new())
            .app_data(web::Data::new(AppState {
                db: db.clone(),
                cache: cache.clone(),
            }))
            .app_data(web::Data::new(service.clone()))
            .app_data(web::Data::new(cfg.clone()))
            .app_data(web::Data::new(db.clone()))
            .app_data(web::Data::new(cache.clone()))
            .app_data(http_snapshot_data.clone())
            .app_data(prometheus_handle_data.clone())
            .route("/health", web::get().to(health_check))
            .route("/metrics", web::get().to(prometheus_handler))
            .configure(api::route::init_routes)
    })
    .bind(&bind_addr)?
    .run()
    .await?;

    tracing::info!("Server stopped, shutting down room workers");
    let _ = shutdown_tx.send(());
    let _ = worker_handle.await;
    tracing::info!("Room workers stopped");

    Ok(())
}

async fn run_migrations(db: &AppDatabase) -> anyhow::Result<()> {
    tracing::info!("Running database migrations...");
    Migrator::up(db.writer(), None)
        .await
        .map_err(|e| anyhow::anyhow!("Migration failed: {:?}", e))?;
    tracing::info!("Migrations completed");
    Ok(())
}

async fn health_check(state: web::Data<AppState>) -> HttpResponse {
    let db_ok = db_ping(&state.db).await;
    let cache_ok = cache_ping(&state.cache).await;

    let healthy = db_ok && cache_ok;
    if healthy {
        HttpResponse::Ok().json(serde_json::json!({
            "status": "ok",
            "db": "ok",
            "cache": "ok",
        }))
    } else {
        HttpResponse::ServiceUnavailable().json(serde_json::json!({
            "status": "unhealthy",
            "db": if db_ok { "ok" } else { "error" },
            "cache": if cache_ok { "ok" } else { "error" },
        }))
    }
}

async fn db_ping(db: &AppDatabase) -> bool {
    db.query_one_raw(sea_orm::Statement::from_string(
        sea_orm::DbBackend::Postgres,
        "SELECT 1",
    ))
    .await
    .is_ok()
}

async fn cache_ping(cache: &AppCache) -> bool {
    cache.conn().await.is_ok()
}